(;GM[1]FF[4]SZ[19]
GN[Counting by twos]
PC[http://senseis.xmp.net/?BlockCounting]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?BlockCounting

Counting by twos]
PL[B]

AB[da][db][dc][dd][ae][be][ce][de]
AW[ea][eb][ec][ed][ee][af][bf][cf][df][ef]
LB[aa:a][ba:b][ca:c][ab:a][bb:b][cb:c][ac:d][bc:e][cc:f][ad:d][bd:e][cd:f]


;LB[aa:a][ba:b][ca:c][ab:a][bb:b][cb:c][ac:d][bc:e][cc:f][ad:d][bd:e][cd:f]
)
